1. Field of the Invention
The present invention relates to an apparatus for controlling operations of an object such as an artificial satellite in orbit after launching.
2. Prior Art
FIG. 1 illustrates an operations control apparatus according to a prior art as disclosed in the Japanese Patent Laid-Open No. 62-70939. The operations control apparatus as shown in the drawing consists, in general, of a ground reception/transmission unit 2 adapted to execute transmission and reception processing of the telemetry data to be received from an artificial satellite 1 and the command data, etc. to be transmitted to the artificial satellite, a data processing unit 3 adapted to process these data, a data diagnosis unit 4 adapted to diagnose these data and an operations console unit 5 which is equivalent to an input/output unit comprising a cathode ray tube and a key board, these components being in general use, is employed for use in displaying a graphic diagram on a screen of a cathode ray tube or inputting a command by an operator from the key board, and serves as the interface between an operator and these units described above.
The above-described data processing unit 3 incorporates in constitution of the software (algorithm) shown in FIG. 2 the respective means for the software comprising a telemetry data processing means 11, a command data processing means 12, an orbit/attitude determining means 13, an orbit/attitude control and planning means 14, an event controller means 15, a common data base means 16, and a simulation means 17. In the data diagnosis unit 4 mentioned above, there is incorporated software for a diagnosis means 18 normally referred to as "an expect system" which comprises software for data diagnosis, comprising the knowledge data base section 18a and the inference function section 18b.
Operation of the operations control apparatus as described above will next be explained. According to the operations control apparatus for an artificial satellite which is constituted as above described, the telemetry data and the ranging data from the artificial satellite are input by way of the ground reception/transmission unit 2 to the data processing unit 3, where the respective processing will be carried out by the means 11-14 shown in FIG. 2.
In FIG. 2, the event controller means 15 is assumed to determine the order of activation of the means 11 through 18 and the means 11-14 will be activated in accordance with a predetermined processing order unless an external interruption is caused.
The manner of operation of the event controller means 15 will next be explained by referring to FIG. 3. In FIG. 3, S81 designates the external interruption step where a decision is made as to whether the event controller means 15 has been externally interrupted by an operator by using, for example, the operation console unit 5 including an input device such as a key board or the like so as to stop the processing. If there has been no such interruption, the process proceeds to the normal processing step S82 so that the respective means 11-14 will be activated in a predetermined processing order. Then the process proceeds to the step S83 where the common data base 16 will be activated to write the result of the processing therein. Then the process proceeds to the step S84 where the diagnosis means 18 will be activated and the data of the processing results will be diagnosed. After that, the process returns to the step S81.
In the mean time if it is found in the step S81 that the event controller means 15 has been externally interrupted, the process proceeds to the step S85 where the designated means will be caused to be activated and executed in accordance with the external request made by an operator and a decision is made in the step S86 whether the predetermined processing has been entirely completed or not. If confirmation of completion of the entire processing operation is not given, the process is still incomplete and proceeds back to the step S81.
As explained above, by means of the event controller means 15, the respective processing is automatically executed under normal conditions, while the processing can be executed as instructed by an operator owing to the external interruption even if any abnormal condition is caused.
The manner of operation in the case of the data diagnosis by using the simulation means 17 and the diagnosis means 18 will next be explained.
The simulation means 17 provides a simulation program which may simulate in advance the movement of an artificial satellite and is used as a so-called computer simulation by which the movement of an artificial satellite when the orbit control and the attitude control will be executed will be assumed and computed by the simulation means 17 before the orbit and attitude control of the artificial satellite will be actually executed.
The diagnosis means 18 provides software (or a program) which is normally called "expert system" in the field of knowledge engineering and artificial intelligence, and comprises a knowledge data base section 18a and inference function section 18b. It is activated in the data diagnosis unit 4 as described above and executes the data diagnosis processing.
The above-mentioned knowledge data base section 18a constitutes a data base comprising an aggregate of the rules for the decision criteria of the data diagnosis. An example of the diagnosis rule for the data for operations control will be explained by referring to FIG. 4. In FIG. 4, the respective rules 91-95 each consist of an assumption part 90A and a conclusion part 90B, wherein the assumption part 90A corresponds to a subordinate clause such as "if . . . ", and the conclusion part 90B corresponds to a clause such as "then . . . ". For example, what is meant by rule 1 (91) is "If the temperature of the fuel tank for the artificial satellite is out of the range from 15.degree. C. to 30.degree. C., the temperature of the fuel tank is abnormal". The aggregate of such rules comprises the knowledge data base 18a.
The above-mentioned inference function section 18b is constructed with a general algorithm which is generally called the "inference engine" or the like in the field of knowledge engineering and artificial intelligence. More specifically, it is provided in the form of software that, for example, allows an inference to be made from a result by way of a so-called syllogism or the like, and is operable when making an inference with the results of diagnosis from the aggregate of the "if . . . , then . . . " rules.
Operation for diagnosing the operations control data for an artificial satellite by using the respective means 15-18 as explained above will now be explained by referring to FIG. 5. FIG. 5 is a flow chart for explaining operation of the data diagnosis, wherein if the data diagnosis function is activated (or started) by the event controller means 15 described above, then the systematic diagrams of the overall system of the artificial satellite and the subsystem are displayed on the operation console unit (Step S101). The failure occurring part (or the abnormal part) is displayed as discriminated by color on the systematic diagram as described above in accordance with the result of the data diagnosis based on the diagnosis means 18 (Step S102). Then diagnosis of a failure is executed (Step S103). A countermeasure for the failure is prepared (Step S104). This countermeasure for the failure is also contained in the above-mentioned rules and such a countermeasure is automatically selected depending on the failure. Simulation at the time of executing this countermeasure is performed by using the simulation means 17 and the result is thereby assumed (Step S105). At the end of the procedure, command data for executing the countermeasure is prepared and transmitted to the artificial satellite (Step S106).
Since the software means incorporated in the operations control apparatus according to a prior art is constituted in the manner as above explained, at the time of normal processing by means of the event controller means 15, the respective processing will be executed only in accordance with the predetermined processing order, such that processing cannot be optimized depending on the situations in the manner of on-line processing by altering the processing order as desired. Accordingly, not only in operations control of a single artificial satellite but also in simultaneous operations control of a plurality of artificial satellites according to the normal processing method of a prior art, a specialist has to always watch the processing order and execute correction of the processing order depending on the failure, resulting in a more complicated processing operation and the expenditure of more time.
Furthermore, the diagnosis rules which are to be contained in the knowledge data base section 18a of the diagnosis means 18 must be revised for each use in diagnosis of operations control of an artificial satellite by a specialist in the field of artificial satellites, in accordance with the design values at the time of designing which are used as the reference values, and addition and modification for the diagnosis rule currently in use also have to be executed by a specialist, with the result that a tremendous amount of work and time by a number of specialists had to be expended during the period of operation of an artificial satellite.